1. Field of the Invention
The present invention relates to a plasma processing apparatus in which plasma is generated in a processing chamber and a substrate is processed therein, and a plasma processing method.
2. Description of the Related Art
In substrate processing such as etching and film formation in manufacturing processes of a semiconductor processing device, a liquid display device, or the like for example, processing using plasma is widely performed.
Usually, plasma processing is performed in a plasma processing apparatus. In this plasma processing apparatus, electrodes opposing each other vertically are provided in a processing chamber, in which plasma is generated by supplying a radio-frequency power to one or both of the electrodes, and then plasma processing of a substrate is performed.
In recent years, there has been developed a plasma processing technique to apply a superposed radio-frequency power to an electrode by supplying two or more radio-frequency powers having different frequencies to one electrode. In Japanese Patent Application No. 2001-127045, there is disclosed a plasma processing technique using a superposed radio-frequency power by supplying two radio-frequency powers having different frequencies to an upper electrode, where the upper electrode and a lower electrode are arranged to oppose each other.
In the plasma processing technique described in Japanese Patent Application Laid-open No. 2001-127045, a first radio-frequency power for exciting a processing gas into plasma is supplied to the upper electrode, and a second radio-frequency power having a frequency lower than that of the first radio-frequency power for drawing ions in the plasma into a substrate is supplied to the lower electrode on which the substrate is mounted. Further, a third radio-frequency power having a frequency lower than that of the first radio-frequency power and higher than that of the second radio-frequency power is supplied to the upper electrode and superposed on the first radio-frequency power. Then phases, frequencies and outputs of the second radio-frequency power and the third radio-frequency power are adjusted to uniformize the plasma, and thereby processing of the substrate is performed uniformly.